CODE EXPERT: Karin Tsai writes computer code for the language-learning app Duolingo.

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Computer Coder

Karin Tsai is helping develop a popular app that allows people to learn new languages

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Studying a new language, like French, German, or Japanese, has gone digital. Karin Tsai aims to help people learn just about any language on the planet—from Czech to Vietnamese—right on their smartphones, tablets, or computers.

Tsai works for Duolingo, a company in Pittsburgh, Pennsylvania, that makes interactive language-learning software. As a computer programmer, she writes code, or instructions, that allows the app to function. Science World spoke with Tsai about how she became interested in computer science, what it’s like to develop software, and the current push to get more young people—particularly girls—into coding.

How did you get interested in computer science?

Many of my colleagues at Duolingo started coding early in their lives, but I didn’t know anything about computer science until my freshman year of college. When I started college at Princeton University in New Jersey, I originally wanted to be a doctor. But then I took a required computer class and it set me on an entirely different path. I was drawn to the problem-solving aspect of coding. It was fascinating to see what you could create through code. I switched my major to computer science and enrolled in graduate school to get my Ph.D. in the same field.

How did you come to work at Duolingo?

My Ph.D. adviser, Luis von Ahn, and a fellow student started Duolingo as a project in graduate school at Carnegie Mellon University in Pittsburgh. I worked on it along with other students. The project eventually became the Duolingo app, and von Ahn became the company’s CEO. I now work for the start-up. I like that it gives me an opportunity to work on something educational to make a difference in people’s lives. Duolingo’s mission is to provide free language education to anyone. Today, more than 200 million people use the program.

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WRITING IN CODE: Tsai uses this type of code, called Python.

What is it like to work as a coder?

My main goal each day is to create awesome software that helps people. I write back-end code, which controls the data the app needs to function. I also write front-end code, which enhances how easily a person can interact with and navigate software. We call that the user experience.

One of the most satisfying and impactful projects I’ve worked on is the Duolingo Language Incubator. This part of the app lets volunteers suggest translations or new sentences to be considered for language courses that are still in development at Duolingo. It also aims to revive dying languages, such as Irish, and even brings fictional languages, like Star Trek’s Klingon, to real life.

What do you like best about your job?

I love hearing positive stories from users about how our app helped them. Some say learning a new language allowed them to have a better time visiting another country. Some users even say that they were able to get a better job by learning a new language through Duolingo.

What’s it like being a female software engineer?

I’ve been fortunate that my company is extremely inclusive, but only 18 percent of software engineers are women. That’s not enough. I’d like more companies to make it a priority to hire more women coders. Even though my industry has come a long way, we have so, so much further to go.

It’s also important that we start teaching girls to code when they’re young—in elementary school or even sooner (see Girls Who Code). Parents and educators need to make sure that girls know that science, technology, engineering, and math (STEM) fields are not exclusively for men. Even though the software industry is starting to be more aware of it, we have a lot of work to do.

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